The present invention relates to a distillation apparatus having applicability to air separation in which a main heat exchanger and one or more distillation columns are enclosed within a sleeve-like containment. More particularly, the present invention relates to such an apparatus in which a distillation column is suspended within the containment from the main heat exchanger or from a head condenser so that the distillation column assumes a vertical orientation under influence of gravitational force.
Mixtures are distilled by contacting liquid and vapor phases of the mixture on liquid-vapor contact elements contained within a distillation column. The liquid-vapor contact elements can be trays, random packing and structured packing. Constant vapor and liquid flow rates are desired across the distillation column in order the distillation column to be efficiently utilized and to have predicable performance characteristics. In order to promote constant liquid and vapor flow rates, distillation columns are erected so that they will assume a vertical orientation. However, in case of small plants, for instance, packaged air separation plants which are encased in vacuum insulated enclosures, the assurance of vertical orientation can be problematical. One attempt to solve this problem can be found in U.S. Pat. No. 5,205,042. In this patent, a liquid nitrogen assist plant is disclosed that employs a distillation column connected to a storage container. The distillation column and storage containing are enclosed within a vacuum insulated container. A suspended mass and locator ring, referable to the orientation of the distillation column, are used to level the vacuum insulated container so that the distillation column will be erected in the necessary vertical orientation.
As will be discussed, the present invention provides a distillation apparatus in which the distillation column is self-leveling and thus, the deployment of the apparatus of the subject invention is far simpler than prior art plants such as packaged air separation plants.